Tube / pipe generator

The generators shown in the pictures use plastic tube of diameter about a = 4cm (see diagram). Discs were cut from sheet plastic and glue-gunned into place and used as formers for the coils. Two small holes were drilled into the pipe to take the crank handle. The magnets were so strong they held themselves in place on the iron crank. The magnets are the same ones used in the shake-a-gen see:
shake-a-gen page

Two versions were made up to show how power could be produced in terms of the current and voltage. The first (top left) has a total of 1000 turns (2 x 500) of 35 SWG and can power a few LED's cranking the handle at a steady slow pace and produces 3 - 4V at ca. 0.2A. The second version (top right) has 20 turns (2 x 10) of 12 SWG. This produces much less voltage (ca. 20/1000 = 1/50th of the 1000 turn gen) and so wont power an LED but because the wire is very thick the internal resistance of the generator is very low. It can therefore produce much higher current than the first. Connecting the second generator to an AC low resistance amp meter showed it produced ca. 10's mV but at 5-10 amps!

Each set of coils will produce an AC voltage so one needs to make sure the coil sets are wired together in series correctly to add the voltages. If you dont get any output from the generator try reversing the connections to only one of the sets of coils. You can also try wiring the coils in parallel to add the currents instead (again, make sure they are wired correctly).

The generator poduces a good sine wave AC voltage and so if two LEDs are wired back to back and across the generator output one LED only will light at any one time depending on the direction of the current (LED are light emitting diodes and so only pass current in one 'direction').